1. Field of the Invention
The present invention relates to a compound protective helmet, and more particularly, to one that allows reliable visor lift operation, and firm securing of the visor when closed.
2. Description of the Prior Art
In the prior art, a chin protector is formed in front of the bubble of a protective helmet, and a window framed with a visor is provided above the chin protector. FIGS. 1 through 4 of the accompanying drawings show the structure and visor operation of the prior art. Referring to FIGS. 1, 2, and 3, the prior art helmet comprises a bubble 10, a visor 20, and a chin protector 30 are pivoted to the bubble 10. A securing and release device 40 is fixed at the inner edge of the chin protector 30 to provide a full mask protective helmet by having the securing and release 40 secured in the grooves 101 provided at both sides of the bubble 10. The securing and release device 40 is comprised of two hooks 401 linked with a cable 402. The cable 402 is connected to a press member 403 and a resilient element 404 that presses against the press handle 403. Therefore, when said hooks 401 of the securing and release device 40 are secured in the grooves 101 of the bubble, the protective helmet is a full mask. To lift the visor 20, the press member 403 is pressed to pull the cables 402, in turn, the hooks 401 disengage from the grooves as illustrated in FIG. 3.
Now referring to FIG. 4, once the hooks 401 clear the grooves 101, the chin protector 30 and the visor 20 are lifted up to a certain point to form a semi-mask protective helmet. To restore to full mask as illustrated in FIG. 1, the chin protector is pulled down to let the hooks slide along the bubble 10 to fall into the grooves 101 and to be secured there. Though the prior art gives the advantage of easy conversion between full and semi mask protective helmet, the following defects in terms of its structural design and practical use are found.
1. Poor securing effects. Since the securing of both the chin protector and the bubble depends on the engagement of the hooks into the grooves provided on the bubble, in practice, the hooks tend to slip away and disengage from the grooves when even a mild force is applied to lift the chin protector.
2. Visor must be lifted in two steps. To lift the visor, a user must first press the press member to release the chin protector before pushing up the chin protector.